Question 10

[matthew]

Dear Dr. Ferdinand,

From the passage:

"It is the difference in expressed genes that accounts for the various functions of discrepant cell types. Therefore, the main concern to cloning became whether the various genes that were turned off in a differentiated cell could be turned back on."

I read this during the exam and thought maybe genes could also have an effect on behaviour? Could that quote have led to choice B and still be correct?

[admin]

You originally posted this as a Q about #6, I edited your question to say Q10 which I believe you were asking about.

You are right that genes can affect behavior but the whole point of cloning is that it creates a genetic duplicate: identical genetically. You've heard about the discussion of "nature vs. nurture" ? Well, this situation is straight forward because the "nature" from a genetic standpoint is identical. So the environment or nurture will, to the greatest degree, be responsible for any differences.

[sahmad3231248]

What you said makes sense. However, the question says "visible and behavioral differences". Now if it was only behavioral difference, I would understand environmental. But how does it account for visible difference?

[admin]

Good point! If you take 5 genetically identical cats, none will have the same pattern of hair colour. Epigenetics is a rapidly growing field that looks at, in part, how the environment affects chemicals which in turn affect which genes are expressed and to what degree. Small differences in the environment changes the way genes can be expressed.

[bravozullu4764]

yeah, but environmental factors ultimately cause a change in gene expression (even if the mechanism is unknown). So answer choice B is the more fundamental reason, and thus (I think) more correct. We keep stressing to pick the answer choice that's most correct, and I think that would be B in this case. otherwise, this is a poor question. . .

[court_visi5845]

[jellywing_2058]

A clone is an identical genetic copy of another organism, therefore answer choice B is wrong because a clone cannot obtain different genes than the ones from the parent.
It is not that the genes are not expressed; It is that they are expressed on different levels due to environmental factors.

[phoenixwarlord]

[jellywing_2058]

Answer choice B is wrong simply because it says that the genes expressed by Dolly are not expressed in the mother. As I had mentioned, there is no such thing as genes NOT expressed in the mother if they are expressed in its clone. The clone and the mother have the same genes, therefore, they are simply expressed on a different level.